LI-COR LI-800 User manual

CO
CO
CO
2Analyzer
Analyzer
Analyzer
®
Environmental Division
Instruction Manual

CO2Analyzer

ii
NOTICE
The information contained in this document is subject to change without notice.
LI-COR MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. LI-COR shall not be liable for
errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material.
This document contains proprietary information which is protected by copyright. All rights are reserved. No part of this document may be
photocopied, reproduced, or translated to another language without prior written consent of LI-COR, Inc.
© Copyright 1998, LI-COR, Inc.
Publication Number 9810-123
Printing History
New editions of this manual will incorporate all material since the previous editions. Update packages may be used between editions which
contain replacement and additional pages to be merged into the manual by the user.
The manual printing date indicates its current edition. The printing date changes when a new edition is printed. (Minor corrections and updates
which are incorporated at reprint do not cause the date to change).
LI-COR, Inc. ●4421 Superior Street ●Lincoln, Nebraska 68504
Phone: [phone] ●FAX: [phone]
Toll-free: 1-800-447-3576 (U.S. & Canada)
e-mail: [email protected] ●www.licor.com

iii
Table of Contents
Section 1. General Description
What’s What................................................................................................................................................................................. 1-1
Features ........................................................................................................................................................................................ 1-3
Precautions ................................................................................................................................................................................... 1-3
Getting Started Tutorial ................................................................................................................................................................ 1-4
Section 2. Power On
Power On ...................................................................................................................................................................................... 2-1
Low Battery Indicator .................................................................................................................................................................. 2-1
Alarms .......................................................................................................................................................................................... 2-2

iv
Section 3. Operation
Installing the PC Communications Software on Your Computer ................................................................................................ 3-1
Setting the Communication Parameters ....................................................................................................................................... 3-2
Cabling ......................................................................................................................................................................................... 3-2
RS-232 Output .............................................................................................................................................................................. 3-2
Initial Setup................................................................................................................................................................................... 3-3
Configuration Window - Setting Operational Parameters............................................................................................................ 3-7
Controls ................................................................................................................................................................................. 3-8
Enable Heater ................................................................................................................................................................. 3-8
Pressure Compensation .................................................................................................................................................. 3-8
DAC Offset Enable ........................................................................................................................................................ 3-8
Span ....................................................................................................................................................................................... 3-10
Reset LI-800 .......................................................................................................................................................................... 3-10
Calibration Window - Setting the Zero and Span......................................................................................................................... 3-11
Record Window - Plotting Data .................................................................................................................................................. 3-13
Y-Axis Page........................................................................................................................................................................... 3-14
X-Axis Page........................................................................................................................................................................... 3-14
Sampling Page ....................................................................................................................................................................... 3-16
Plot Page................................................................................................................................................................................ 3-18
Log File Page......................................................................................................................................................................... 3-19
Analog Output .............................................................................................................................................................................. 3-21
Converting Current Output to ppm CO2............................................................................................................................... 3-24
Using the Terminal Strip .............................................................................................................................................................. 3-25
Connecting the GasHound to the LI-1400 Data Logger............................................................................................................... 3-27

v
Section 4. Theory of Operation
System Overview.......................................................................................................................................................................... 4-1
Optical Bench System .................................................................................................................................................................. 4-2
Section 5. Maintenance
Cleaning the Optical Bench .......................................................................................................................................................... 5-1
Changing the Optical Bench ........................................................................................................................................................ 5-5
Changing the Fuse ........................................................................................................................................................................ 5-7
Appendix A. Specifications
Appendix B. Pin Assignments
Appendix C. List of Suppliers
Warranty

General Description 1-1
General Description
What's What
This procedure should be followed if you have just taken delivery of your
LI-800. Check the packing list to verify that you have received everything that was ordered
and that you have also received the following items:
●RS-232 Cable - (Part #392-04993), used to connect the LI-800 to your computer.
●800-50 Data Communications Software - This Windows® 95 and Windows® NT com-
patible software is used to communicate with your computer. The software is provided
on CD. A complete description of this software can be found in Section 3, Operation.

Section 1
1-2 General Description
●Standard Spare Parts Kit (9980-012) - This kit contains replacement parts for your
LI-800. As you become familiar with the analyzer you will learn which items to keep
close at hand and which items can be stored away. The spare parts kit contains these
items:
Description Qty.LI-COR Part No.
Polyurethane Mounting Feet 4 234-02268
Mounting Screws 4 149-02610
Bev-a-line Tubing 12' 222-01824
Disposable Air Filter 2 300-01961
Quick Connect Unions 2 300-03123
1.6A Fuse 2 439-04537
Cleaning Kit, includes: 1 9980-013
3" Cleaning Swabs 5 610-05314
5" Cleaning Swabs 5 610-05315
O-Rings 4 192-00226
Pre-formed Optical Bench Tubing 4 6580-010

Section 1
General Description 1-3
Features
The LI-800 is an economical high performance, non-dispersive infrared gas analyzer designed
to be used for a wide variety of applications. Some of the LI-800's important features include:
●Optional short (2") and standard long (5.5") interchangeable optical benches can be used
to obtain resolutions of 0-20000 ppm and 0-2000 ppm, respectively. No changes in
calibration polynomials or software need to be made when swapping optical benches.
●Optical benches are fully serviceable by the user; cleaning the optical benches is a simple
process, and does not affect the instrument calibration.
●Simple Windows®software provides for easy user calibration and data output.
Precautions
●The optical bench is maintained at a constant 50 °C. Avoid direct exposure to sunlight or
extremely high temperatures that may elevate the temperature inside the LI-800 case.
●The optical source is sensitive to vibration, and can be damaged by strong vibrations or
jarring. Do not drop the LI-800, or expose it to severe mechanical shock.
●Do not use abrasive cleansers when cleaning the optical bench, as damage to the gold
plating may result. Instructions for cleaning the optical bench can be found in Section 5.
●Always filter air entering the LI-800. A Gelman polypropylene filter is included in the
spares kit.

Section 1
1-4 General Description
Getting Started Tutorial
The following section briefly covers the basic steps you might follow to set up the LI-800 to
collect and record data. Many of these steps are described in greater detail throughout this
manual.
1Install the 800-50 PC Communications Software.
This software is required for setting the zero and span of the LI-800 and for setting up data
communication and data transfer parameters. Installation instructions can be found in Section
3, Installing the Software on Your Computer.
2Determine your jumper settings for analog output (if desired) and
high and low alarm output, if required.
There are 4 jumpers inside the LI-800 case (on the main circuit board), two of which
determine the voltage output ranges on the terminal strip (position #9), and the other two,
which toggle the high and low alarm output between 0-5V (TTL levels) and an open drain
condition.
The default jumper positions are set for 0-5V analog output and 0-5V output for both high and
low alarms. This alarm configuration is suitable for logic devices such as dataloggers. To use
the high and/or low alarms to operate a relay switch, the jumpers should be reconfigured for
open drain output. See Section 2, Alarms, for a description of how to change the alarm
jumper settings; see Section 3, Analog Output, for a description of the voltage output jumpers.

Section 1
General Description 1-5
If the default jumper positions are suitable for your application, or if you do not intend to use
the alarms and/or analog output for your data, proceed to Step 3.
3
+-
12345678910
11 12 13 14
Connect a power source to the LI-800.
Any power source that provides 12-30VDC can be used to operate the LI-800. Bare wire
leads are connected to the terminal strip at positions 1 and 2. Connect the positive lead to
position #1 (12-30VDC), and the negative lead to position #2 (GND).
NOTE: Pull straight out on the face of the terminal strip to remove it; this can make it
easier to connect the wires.
4Connect the RS-232 cable.
Connect one end of the serial cable to the 9-pin Serial I/O port on the LI-800 front panel, and
the other end to a serial port on your computer. If you want to interface to a device with a 25-
pin serial port, a 9-pin to 25-pin adapter must be used; a gender changer may be required in
some cases, also. Tighten the two screws on the ends of the serial cable.
5Connect other output device(s) if desired.
Output devices such as dataloggers and relay switches for high and low alarms are connected
via the terminal strip. A complete description of the terminals can be found in Section 3,
Using the Terminal Strip.

Section 1
1-6 General Description
6Hook up the input air stream and external filter.
Remove the nut from the Flow In fitting and connect a short (12" or so) piece of Bev-a-line
tubing (in the spares kit). Tighten the nut. Place the Balston filter (also in the spares kit) in
the sample airstream before it enters the FLOW IN port on the LI-800.
IMPORTANT: Always install the external air filter before operating the LI-800.
Insert filter into the input airstream before it enters the LI-800. Failure to do this
will lead to contamination of the optical path.
There are some quick connect fittings in the spare parts kit that can be used on either side of
the Balston filter to aid in changing the filter out. Press on the red part of the fitting to release
the tubing.
When using the LI-800 in applications where sample air is particularly dirty, you may
consider stacking two filters in series. For maintenance, replace the filter furthest upstream
from the analyzer with the filter closest to the analyzer and replace the filter closest to the
analyzer with a new filter.

Section 1
General Description 1-7
BALSTON
DFU
®
Grade
Install the new filter(s) with the arrow facing toward the FLOW IN port.
The air inlet and outlet ports should be covered with the dust caps provided or attached to an
air line when the instrument is not in use. This will prevent dust from entering the instrument
downstream from the filters where it can enter the optical path.
Replacement Balston air filters can be obtained from LI-COR (part #300-01961).
7Start the 800-50 PC Communications Software.
When you start the 800-50 program, you will be asked to choose the serial port to which the
LI-800 is connected. The 800-50 Main window appears.

Section 1
1-8 General Description
8Configure the analyzer.
Click on the Configure button in the Main window. Select the CO2range (the 'Span' buttons)
over which you will be measuring CO2. Choose a value for signal averaging, between 0 and
20 seconds. Set values for high and low alarms and corresponding dead bands, if desired. See
Section 2 for a complete description of the alarms. Make sure the Heater is enabled
(checked), and click OK.
9Set the analyzer zero.
Connect a dry, CO2-free gas to the input air stream. Click on the Calibrate button in the Main
window. Click on Zero IRGA. After a few minutes, a message will appear in the status bar at
the bottom of the window that indicates when the IRGA is zeroed.
10 Set the analyzer span.
Connect your span gas to the input air stream. Click on Span IRGA. You will be prompted to
enter the value of the span gas. After a few minutes, a message will appear in the status bar
indicating that the span calibration is completed. Click Quit.

Section 1
General Description 1-9
11 Set up the data collection parameters.
Click on the Record button in the Main window. Click on the Y-Axis, X-Axis, and Plot tabs
to set up the parameters for displaying data on screen, if desired. Click on the Sampling tab
and choose sampling and logging periods (see Section 3, Record Window, for a description of
sampling and logging periods). Click on the Log File tab and choose the data points to be
logged (Point, Mean, Max, Min). Click Save To and choose a data file name and destination.
Click Save. Click Start to begin recording data. A graph with data will appear in the window
and will be logged to the file designated.
12 Click Stop to close the data file and stop recording when you are
done collecting data.

Power On 2-1
Power On
Power On
The LI-800 can be connected to a constant source of AC power by using a transformer that
provides 12-30VDC (12W minimum) to the LI-800. If the LI-800 is powered On with a
battery below 10.5 volts, the analyzer will not power up, and the Low Battery LED on the top
panel will illuminate.
Low Battery Indicator
The low battery LED on the LI-800 top panel will illuminate when the battery voltage drops
below 10.5 volts. The LI-800 will continue to operate with a low battery; there will, however,
be a corresponding reduction in performance.

Section 2
2-2 Power On
Alarms
The LI-800 is equipped with high and low alarms, which can be configured as open collector
or 0-5V output (TTL levels) using jumpers on the main PC board (Figure 2-1). The default
configuration is 0-5V output. Figure 2-2 shows the position of the jumpers for each of the
two alarm conditions.

Section 2
Power On 2-3
Alarm
Jumpers Voltage
Output
Jumpers
LK1 LK2
LK5
LK3
Figure 2-1. Location of alarm jumpers LK1 and LK2.

Section 2
2-4 Power On
3
1
2
3
1
2
High Alarm
1
LK1 LK2
LK1 LK2
Low Alarm
High Alarm
Low Alarm
1
3
1
2
3
1
2
11
Open Drain
Logic (Digital, 0-5V)
Figure 2-2. Position of jumpers for open drain and 0-5V output.

Section 2
Power On 2-5
In addition, a "dead band" value can be set in software for both high and low alarms. To
understand how the alarms and dead band values work, look at the diagram below.
Elapsed Time
CO
2
Concentration, ppm
0
100
200
1000
900
Low Alarm = 100
High Alarm = 1000
High Alarm
activated
Low Alarm
activated
Low Alarm
deactivated
High Alarm deactivated
Dead Band = 100 ppm
Dead Band = 100 ppm
In this chart, the low and high alarm values are set to 100 ppm and 1000 ppm, respectively.
The dead band value in both alarms is set to 100 ppm. When the CO2concentration reaches
1000 ppm, the high alarm is activated, and remains active until the concentration drops below
900 ppm. When the CO2concentration falls below 100 ppm, the low alarm is activated, and
remains active until the concentration rises above 200 ppm. Your choice for the dead band
value(s) depends on your application, and the fluctuation in CO2concentrations over time.